Vegetable oils coming from oilseeds such as canola or soybean or oilfruits such as palm contain chlorophyll. Chlorophyll is removed during many stages of the oil production process, including seed crushing, oil extraction, degumming, caustic treatment and bleaching steps. In the last of these, the bleaching process residual chlorophyll is removed to achieve acceptable levels. This chlorophyll is typically removed from the oil in a bleaching process step involving heating the oil and running it through an adsorbent to remove chlorophyll and other color-bearing compounds that impact the appearance and/or stability of the finished oil. This technology is also used to treat other chlorophyll-containing oils or plant or algal preparations, such as polyunsaturated fatty acid (PUFA) (e.g., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) containing oils.
High level of chlorophyll pigments impart undesirable color and induce oxidation of oil during storage leading to a deterioration of the oil. In the edible oil processing industry, a bleaching step is employed to lower chlorophyll levels to as low as 0.1 ppm to guarantee oil quality in terms of color and organolepticity. Typical desired finished chlorophyll levels are between 0.02 to 0.05 ppm. This bleaching step increases processing cost and reduces oil yield due to entrainment in the bleaching clay.
In plants, chlorophyllase (chlase) is the first enzyme involved in chlorophyll degradation; it catalyzes the hydrolysis of an ester bond in chlorophyll to yield chlorophyllide and phytol.